A power shift transmission is known from the prospectus "Favorit 926" issue E 11/95/10 by the firm "Xaver Fendt GmbH & Co.". The power shift transmission is controllable by a clutch arranged at the input shaft. The clutch is followed by a planet gear that makes it possible to split the power. A hydrostatic drive line and a mechanical drive line are arranged in parallel to each other and following to the planet gear. The parts of the power transmitted by the two drive lines are brought together to a summating output line. An axial piston pump having an adjustable turning angle is provided within the hydrostatic drive line. Two axial piston motors can be controlled by the axial piston pump to attain a great multiplication. The turning angles of the axial piston motors can be only adjusted in common. The axial piston motors work on the one common summating output shaft. A shaft arranged following to the output shaft can be connected to the output shaft by a clutch and via alternatively one of two gear units. In case of low numbers of revolutions of the output shaft and correspondingly low driving speeds, the power is split by means of the planet gear. Approximately 75% of the power is transmitted via the hydrostatic drive line and approximately 25% of the power is transmitted via the mechanical drive line. Consequently, the relatively low operational efficiency within the hydrostatic drive line has a disadvantageous effect. The driving speed always depends on the number of revolutions of the engine since a direct connection via the mechanical drive line is given. In case of great numbers of revolutions and correspondingly great driving speeds, the axial piston motors are changed to a turning angle 0 and therefore block the axial piston pump. Consequently, high pressures and a great power dissipation occur within the hydrostatic drive line. The axial piston motors are driven by the output shaft. This results in additional power dissipation. The great operating efficiency of the mechanical drive line is used during high driving speeds but dissipation occurs always within the hydrostatic drive line.